Made the trip from Boise to San Francisco 2 weeks ago wanted to follow up on the 2 alternate routes most of you suggested. Going over to SF from Boise I flew direct to Klamath Falls - really south of that route near Lake City to cut the corner and then south from Redding to Willows for breakfast and then on into Concord. On the way back I flew direct Concord to Reno area then WMC and then north to Boise. The Norcal and Oakland/Travis Approach controllers were really friendly and helpful - almost going out of their way to help, especially for someone like me who flies alot in the Chicago area and has to deal with generally irritable Chicago area controllers (especially for VRF traffic).
Of the 2 routes the southern route going by way of WMC seems overall better, as well as 60 miles shorter. While the terrain is higher and more rugged from Reno to SAC, the terrian after Reno to the northeast is generally more friendly and flatter than the northern route via Kalmaeth Falls. The terrain between Burns and Lake City and Redding, while not real high, is extremely remote with no ranches, few roads and few if any airports or civilization.
The other big advantage od the southern route is that you can get VFR flight following the entire route, whereas on the northern route from before Burns to Klameth Falls - about 120 or so miles - you cannot get flight following. Also when you cut the corner south and east of Klamath Falls, the terain seems even more remote than between WMC and Boise, which seems to have more roads and ranches along the route. Plus the souternern route is 60 miles shorter. So all in all, I would recommend Boise-WMC-Bay Area if you are trying to do that route in a small airplane.
Thank you again to everyone who gave me suggestions - they were very helpful!! And breakfast at Willows wasn't bad, and the fuel prices there were even better.
Thank you again -